Arabs used the Abjad system for numbers before the introduction of 0-based counting systems. In Abjad each letter of the 28 in the writing system has a number. Like:
a = 1, b = 2, c = 3, ..., j = 10, k = 20, l = 30, ..., t = 100, u = 200, ...
There is no value in the position (like with Roman numbers where a smaller value after a bigger value subtracts it). So "cab" is 6, but "abba" is also 6. Now you can make words and rhymes to remember numbers. Saves you all the mental images of Sinatra kicking superman :)